Chromiferous azo dyestuffs



Patented Jan. 12, 1932 UNITED STATES PATENT OFFICE HANS KRZIKALLA, OF MANNHEIM, GERMANY, ASSIGNOR T0 GENERAL ANILINE WORKS,

INC.,'OF'NEW YORK, N. Y., A CORPORATION OF DELAWARE momrrmous AZO DYESTUFFS No Drawing. Application filed November 10, 1980, Serial No. 494,809, and in Germany November 18, 1929.

The present invention relates to complex chromium compounds of azo dyestuffs particularly suitable for dyeing leather.

I have found that the complex chromium compounds of azo dyestuffs corresponding to the formula:

OH I

coon 1103s N=N OH reflux condenser with solutions of chromic' formate acetate, fluoride or the like. The resulting chromium compounds of the dyestuffs yield especially on leather beautiful,

full, uniform brown or red dyeings which have a very good fastness to light.

The following example will further illustrate the nature of this invention, but the invention is not restricted thereto. The parts are by weight.

E wample OOOH HO on as HOOK,

is then isolated by evaporating the solution or by salting out. A brownish powder is obtained which dissolves in concentrated sul- OH Hm :NOOH.

in the manner described a dyestuff is obtained dyeing leather fast, full and red shades.

lVhat I claim is 1. As new articles of manufacture the complex chromium compounds of azo dyestuffs corresponding to the formula:

COOH H018 N=N OH,

the said chromiferous dyestuffs yielding uniform brown or red dyeings on leather.

2. As a new article of manufacture the complex chromium compound of the azo dyestufl' corresponding to the formula:

COOH

the said chromiferous dyestuff dissolving in concentrated sulphuric acid giving an orange coloration and yielding a uniform brown dyeing on leather.

In testimony whereof I have hereunto set my hand.

HANS KRZIKALLA. 

